Apparatus for controlling the operation of drawers

ABSTRACT

A filing cabinet which includes a number of vertically stacked housings each of which has a drawer and at least one interlocking assembly which has first and second slide members which are moved apart when the drawer is opened and which then abut a slide member or members of a respective adjacent drawer or drawers to prevent such drawer or drawers from being opened.

BACKGROUND OF THE INVENTION

This invention relates to apparatus for controlling the operation of a plurality of drawers which may be stacked one above the other for example in a filing cabinet or similar arrangement.

Each of the drawers in a filing cabinet may contain a large number of files and consequently may be fairly heavy. A filing cabinet may include four or even more drawers stacked one above the other in a vertical array. If an uppermost drawer is withdrawn to a position at which files inside the drawer can be accessed, while the drawer is maintained engaged with a housing in which the drawers are mounted, then a substantial moment can be exerted on the housing which tends to rotate the housing. Normally the design of the filing cabinet is such that if a single drawer only is withdrawn the cabinet is stable. On the other hand if two drawers are simultaneously withdrawn from the housing the resulting moment may be so great that the filing cabinet topples and can cause serious injury or damage.

In order to counter the aforementioned problem it is known to provide a filing cabinet with an interlocking arrangement which permits only one drawer to be withdrawn at a time. Although this type of arrangement permits only one drawer to be accessed at a time it has the disadvantage that it is custom-made for the particular housing. The purchase price of a filing cabinet with a plurality of drawers can be substantial and in many instances a need exists for a small filing cabinet with, say, two drawers to which additional drawers can be added as filing requirements grow.

It is possible to provide a modular filing cabinet which permits the addition of drawers, according to requirement, until a maximum size is reached but, to the applicant's knowledge there is no easy way of providing an interlocking arrangement which works effectively and automatically between a plurality of drawers the number of which is varied on an ad hoc basis.

SUMMARY OF INVENTION

The invention provides an interlocking assembly for a drawer which includes first and second slide members which are movable from respective rest positions to respective limiting positions and an actuator which is movable, upon movement of the drawer, between inoperative and operative positions, and wherein the slide members are at their respective rest positions when the actuator is at the inoperative position and the actuator, when moved to the operative position, causes the slide members to move to the respective limiting positions.

Preferably the slide members are elongate and in-line with each other.

The slide members may include respective opposing ends which are close together when the slide members are at the respective rest positions and which are moved further apart when the slide members are moved to the respective limiting positions.

The actuator may be moved between the opposing ends of the slide members when moved to the operative position.

The assembly may include biasing means which acts on the actuator and which tends to restore the actuator to the inoperative position.

In one form of the invention the drawer is mounted for movement on a guide mechanism and the actuator is movable by the guide mechanism.

Preferably the actuator is movable between the inoperative and operative positions in a direction which is the same as a direction in which the drawer is moved between closed and withdrawn positions.

The invention also provides a housing for a drawer which includes a frame and at least one interlocking assembly of the aforementioned kind engaged with the frame, and wherein an upper end of the first slide member is exposed on an upper surface of the frame and a lower end of the second slide member is exposed on a lower surface of the frame.

A drawer may be engaged with the frame and may be movable into and out of the frame by means of a slide mechanism of a kind which is known in the art and which for this reason is not further described herein.

The invention also extends to a cabinet which includes a plurality of housings, each of the aforementioned kind, the housings being arranged stacked one above the other in a vertically extending array with the exposed upper end of a first slide member of a lower interlocking assembly acting on an exposed lower end of a second slide member of an adjacent upper interlocking assembly. This arrangement causes the interlocking assemblies automatically to interact with each other.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is further described by way of example with reference to the accompanying drawings in which:

FIG. 1 is a side view in cross section of a filing cabinet according to the invention; and

FIGS. 2 and 3 respectively show portions of the cabinet of FIG. 1 in closed and open drawer positions respectively.

DESCRIPTION OF PREFERRED EMBODIMENT

FIG. 1 illustrates a cabinet 10 with a lower housing 12A and an upper housing 14A stacked over the lower housing. The housings include drawers 100A and 100B respectively. Each drawer is mounted for sliding movement between a closed position and a withdrawn position on respective guide mechanisms 200A and 200B. Each guide mechanism is of substantially conventional construction and consequently is not further described in detail herein. Each guide mechanism includes an elongate rod 202 which is movable, when a drawer is moved from a closed to a withdrawn position, from an inner position shown for the guide mechanism 200B to an outer position shown for the guide mechanism 200A.

The housings 12A and 14A are of modular construction and therefore it is possible to add an upper housing to a lower housing, or remove an upper housing from a lower housing on which it is located, at any time. Catch and fastening members generally designated 204, of any appropriate kind, are used to secure the housings to one another.

FIGS. 2 and 3 respectively show a portion of a guide mechanism in the cabinet of FIG. 1 in closed and open drawer positions. Each drawer has associated with it an interlocking assembly 206 which is actuated by movement of the elongate member 202. The interlocking assembly 206 includes first and second slide members 260 and 264 which are in-line, which are spaced from each other, and which are positioned on upper and lower sides of the guide mechanism 200. The slide members are movable in guide components 210 and 212 respectively. The slide members have arcuate plastic covers 214 fitted to their extremities. The slide members are biased towards each other by means of springs 266, shown somewhat schematically in FIG. 2.

An actuator 216 is mounted for sliding movement between an inoperative position shown in FIG. 2 and an operative position shown in FIG. 3, in the same direction as the direction in which the drawer is moved when it is moved from a closed position to a withdrawn position. The actuator includes cam surfaces 218 and 220. A spring 222 is fixed to a rear end of a stationary component 224 of the guide mechanism 200 and to a trailing end 226 of the elongate member 202. This end is also attached to the actuator 216.

From FIG. 1 it is evident that the slide members of each interlocking assembly are in-line with each other and are also aligned with the slide members of the remaining drawer or drawers in the cabinet.

When the actuator 216 is moved to the operative position shown in FIG. 3, by movement of a corresponding drawer to a withdrawn position, the cam surfaces 218 and 220 ride against the arcuate surfaces of the corresponding covers 214 and the slide members are thereby moved apart with a low friction action from the rest positions shown in FIG. 2, further compressing the springs 266, to the limiting positions shown in FIG. 3.

Extremities of the slide members, shown in FIG. 1, are thus brought into contact with extremities of corresponding slide members of adjacent interlocking assemblies associated with respective drawers above and below (if this is the case) the slide members 260 and 264. The outwardly moving slide members 260 and 264 prevent the corresponding slide members of each adjacent interlocking assembly from being moved downwards or upwards, as the case may be, and consequently the drawers associated with those slide members can not be withdrawn.

As the withdrawn drawer is moved to its closed position the spring 222 urges the actuator 216 to the inoperative position shown in FIG. 2. The opposed ends of the slide members 260 and 264 are then moved towards one another by means of the biased springs 266. In other words if a different drawer is moved from a closed to a withdrawn position its slide members are moved with movement being transferred from one slide member to another, so that only the drawer in question can be withdrawn and the other drawers remain locked in their closed positions.

The interlocking mechanisms on each drawer and housing, only abut the interlock mechanisms of adjacent drawers but otherwise are not connected thereto. Thus, although the interlocking mechanisms interact with one another, as described, each housing is essentially a stand-alone unit and can be coupled to another housing (or housings) or detached therefrom, without affecting the interlocking action which automatically operates irrespective of the number of drawers or housings in a cabinet. Each drawer could include two or more of the interlocking mechanisms to increase the locking or safety effect. Each mechanism would function in the manner described. 

1. An interlocking assembly for a drawer which includes first and second slide members which are movable from respective rest positions to respective limiting positions and an actuator which is movable, upon movement of the drawer, between inoperative and operative positions, and wherein the slide members are at their respective rest positions when the actuator is at the inoperative position and the actuator, when moved to the operative position, causes the slide members to move to the respective limiting positions.
 2. An assembly according to claim 1 wherein the slide members are elongate and in-line with each other.
 3. An assembly according to claim 1 or 2 wherein the slide members include respective opposing ends which are close together when the slide members are at the respective rest positions and which are moved further apart when the slide members are moved to the respective limiting positions.
 4. An assembly according to claim 3 wherein the actuator is moved between the opposing ends of the slide members when moved to the operative position.
 5. An assembly according to any one of claims 1 to 4 which includes biasing means which acts on the actuator and which tends to restore the actuator to the inoperative position.
 6. An assembly according to any one of claims 1 to 5 wherein the drawer is mounted for movement on a guide mechanism and the actuator is movable by the guide mechanism.
 7. An assembly according to any one of claims 1 to 6 wherein the actuator is movable between the inoperative and operative positions in a direction which is the same as a direction in which the drawer is moved between closed and withdrawn positions.
 8. A housing for a drawer which includes a frame and at least one interlocking assembly according to any one of claims 1 to 7 engaged with the frame, and wherein an upper end of the first slide member is exposed on an upper surface of the frame and a lower end of the second slide member is exposed on a lower surface of the frame.
 9. A housing according to claim 8 wherein the drawer is engaged with the frame and is movable into and out of the frame.
 10. A cabinet which includes a plurality of housings, each housing being according to claim 8 or 9, the housings being arranged stacked one above the other in a vertically extending array with the exposed upper end of a first slide member of a lower interlocking assembly acting on an exposed lower end of a second slide member of an adjacent upper interlocking assembly.
 11. Apparatus for controlling the operation of a plurality of vertically stacked drawers, the apparatus including a plurality of interlocking assemblies, one for each respective drawer, each interlocking assembly being according to any one of claims 1 to
 7. 12. Apparatus for controlling the operation of a plurality of vertically stacked drawers, the apparatus including a plurality of interlocking assemblies, one for each respective drawer, each interlocking assembly including an actuator which is movable between an inoperative position and an operative position, a first slide member on one side of the actuator, and a second slide member on an opposing side of the actuator, each slide member being slidably movable between respective rest and limiting positions, the actuator causing the slide members to move to the limiting positions when a respective drawer is withdrawn from a housing to which the apparatus is fixed, the slide members of all the interlocking assemblies being co-linear with each other with the first slide member of a lower interlocking assembly acting on the second slide member of an adjacent upper interlocking assembly.
 13. A filing cabinet which includes a number of vertically stacked housings each of which has a drawer and at least one interlocking assembly which has first and second slide members which are moved apart when the drawer is opened and which then abut a slide member or members of a respective adjacent drawer or drawers to prevent such drawer or drawers from being opened. 